1. Technical Field
The present invention relates to a semiconductor device and a manufacturing method therefore.
2. Related Art
As MOS transistors that handle a large amount of power, DMOS (Double diffused Metal Oxide Semiconductor) transistors have been known.
U.S. Patent Application Publication No. 2008/0061368 (Patent Document 1) discloses a DMOS transistor including a gate oxide film and a gate electrode that are positioned on a first surface of a semiconductor substrate and an n-type source contact region and a p-type body contact region that are positioned to be in contact with the first surface at positions different from a position of the gate electrode in a plan view relative to the first surface of the semiconductor substrate. In Patent Document 1, a sidewall oxide film is formed on a side surface of the gate electrode. In an inter-layer insulating film covering the semiconductor substrate and the gate electrode, contact holes for connecting to the n-type source contact region and the p-type body contact region are formed.
In the structure disclosed in Patent Document 1, it is necessary to design the layout of the gate electrode and the contact hole taking the processing accuracy of the gate electrode and the processing accuracy of the contact hole into consideration for preventing the occurrence of leakage current between the gate electrode and the contact hole. For this reason, there is a problem that it is difficult to reduce an element area.